Plant Cells, Tissues, and Organ Systems Overview

cell specialization

the process by which cells develop from similar cells into cells that have specific functions within a multicellular organism

cell differentiation

a stage of development of a living organism during which specialized cells form

tissue

a cluster of similar cells that share the same specialized structure and function

organ

a combination of several types of tissue working together to perform a specific function

meristematic cell

an unspecialized plant cell that gives rise to a specific specialized cell

transpiration

the process of water movement through a plant and its evaporation from aerial parts, especially from the leaves

gall

a growth on a plant caused by the activity of insects, fungi, or bacteria

storage vacuole

a large vacuole in plant cells that stores nutrients and waste products

chloroplast

the organelle where photosynthesis occurs in plant cells

epidermal cell

a cell that forms the outermost layer of a plant's organs, providing protection and regulating gas exchange

dermal tissue

the outermost covering of the plant's organs, acting as a barrier between the plant and its external environment

ground tissue

plant tissue that has several functions, including storage, photosynthesis, and support

vascular tissue

plant tissue responsible for the transport of water, nutrients, and food throughout the plant

photosynthesis

the process by which green plants use sunlight to synthesize foods with the help of chlorophyll

gas exchange

the process of exchanging oxygen and carbon dioxide between a plant and its environment

dormant

a state in which a plant is inactive during extreme weather conditions, such as cold or very hot weather

permanent embryos

a term used to describe meristematic cells due to their lifelong ability to produce new tissues and organs

specialized cells

cells that have developed specific functions and structures to perform particular tasks in an organism

multicellular organism

an organism composed of multiple cells that work together to perform various functions

mitosis

the process by which a cell divides to produce two identical daughter cells

proteins

molecules produced by genes that determine the function of a cell

genetic information

the hereditary information encoded in the DNA of an organism's cells

cell wall

a rigid layer that provides support and protection to plant cells

Xylem cells

Dead tubular cells, laid end to end, transport water and minerals from plant roots to other parts of the plant.

Phloem cells

Living tubular cells, joined end to end, transport sugars from leaves to other parts of the plant.

Vascular tissue

Performs the critical job of transporting water, nutrients, and sugars throughout the plant and helps to provide physical support for the plant's body.

Meristematic cells

Produce new cells that differentiate into the specialized cells that make up different plant tissues.

Terminal bud

The most active growth area in a plant, containing meristem for new tissues.

Lateral bud

Dormant buds that have the potential to produce new branches, leaves, and flowers.

Cambium

A layer of meristematic cells that causes the stem to thicken.

Auxin

A plant hormone produced in actively growing areas that controls the growth of cells below and behind them.

Cell elongation/growth and differentiation

Processes that occur in meristematic cells allowing plants to grow and develop specialized tissues.

Photosynthesis

The process by which leaves provide a large surface area to convert sunlight into glucose.

Starch

A storage form of glucose that is produced when photosynthesis generates more glucose than the leaf needs.

Embryo development

The process through which the cells, tissues, and organs of multicellular animals are formed.

Plant organs

Different kinds of tissues that combine to make up organs such as leaves, stems, roots, and flowers.

Growing plants

Push upward, downward, and outward due to rapidly dividing meristematic cells at the tips of roots and branches.

Light-collecting organs

Organs such as leaves that can die and be replaced by new, more efficient leaves as they become less efficient with age.

Chemical signals in plants

Auxin silences the expression of genes in lateral buds, promoting upward growth over outward growth.

Removal of terminal bud

Eliminates the auxin that inhibits lateral growth, allowing lateral buds to begin to divide and specialize.

Plant growth

Occurs actively near the terminal bud and is influenced by the presence of auxin.

Reproductive organ

In many plants, this is the flower, which is considered a fourth organ.

Surface area in leaves

A large surface area is essential for photosynthesis, even in leaves that resemble thin needles.

Continuous root growth

Roots grow continuously to ensure there are always fresh roots to absorb water and minerals from the soil.

Plant tissue repair

Plants can form new cells and tissues, as well as new organs, throughout their lives.

Auxin's role in growth

Auxin produced in the terminal bud inhibits the development of cells in lateral buds.

cuticle

A waxy layer that reduces water evaporation from the leaf's surface.

upper epidermal cells

Cells that form the upper protective layer of the leaf and do not perform photosynthesis.

palisade tissue cells

Specialized cells in the leaf that perform most of the photosynthesis.

vascular bundle

Structures that contain xylem and phloem, arranged into veins within the leaf.

xylem

Tissue that delivers water to photosynthesizing cells in the leaf.

phloem

Tissue that picks up sugars produced in the leaf and delivers them to other parts of the plant.

spongy parenchyma cells

Loosely packed cells in the leaf that form a network with open spaces for gas exchange.

stomata

Pores in the leaf that allow for gas exchange, controlled by guard cells.

guard cells

Cells that control the opening and closing of stomata to regulate gas exchange.

lower epidermal cells

Cells that form the lower protective layer of the leaf and facilitate gas exchange.

transpiration

The evaporation of water from leaves.

mesophyll tissue

Tissue located between the upper and lower surfaces of a leaf, consisting of palisade and spongy parenchyma cells.

chloroplasts

Organelles within palisade cells where photosynthesis occurs.

mitochondria

Organelles that perform cellular respiration in palisade cells.

stoma

Singular form of stomata, referring to a pore in the leaf.

water vapour

Water in its gaseous state, involved in photosynthesis and transpiration.

oxygen

A gas produced during photosynthesis that exits the leaf through stomata.

carbon dioxide

A gas that enters the leaf through stomata for photosynthesis.

vascular bundles

Veins in the leaf that ensure every cell is close to a supply of water and nutrients.

palisades

Long poles used in old fortresses, resembling the arrangement of palisade cells.

sponge

A material that has open spaces, similar to the arrangement of spongy parenchyma cells.

leaf cross sections

Prepared slides used to observe the specialized cells of leaves.

compound light microscope

A tool used to observe the structures of leaf cells.

microviewer

An alternative tool for observing the specialized cells of leaves.

stomata

Small openings on the leaf surface that allow for gas exchange.

guard cells

Specialized cells that control the opening and closing of stomata.

epidermal cells

Cells that form the outer layer of the leaf, providing protection.

palisade cells

Columnar cells located beneath the epidermis, responsible for photosynthesis.

spongy parenchyma cells

Loosely arranged cells in the leaf that facilitate gas exchange.

vascular cells

Cells that make up the xylem and phloem, responsible for transport of water and nutrients.

photosynthesis

The process by which plants convert light energy into chemical energy in the form of glucose.

chloroplast

Organelles in plant cells where photosynthesis occurs.

thylakoids

Membrane-bound sacs within chloroplasts that contain chlorophyll.

granum

Stacks of thylakoids in chloroplasts.

lignin

A hard substance that fortifies dead xylem cells, providing strength.

xylem

Vascular tissue that transports water and nutrients from the roots to the rest of the plant.

phloem

Vascular tissue that transports sugars and other metabolic products downward from the leaves.

cell differentiation

The process by which a cell changes to a more specialized type.

glucose

A simple sugar that is an important energy source in living organisms.

oxygen

A gas produced as a byproduct of photosynthesis, essential for cellular respiration.

carbon dioxide

A gas taken in by plants during photosynthesis.

water

A vital component for photosynthesis, absorbed by plant roots.

high energy molecules

Molecules that store energy, such as glucose, produced during photosynthesis.

cellular respiration

The process by which cells convert glucose and oxygen into energy, carbon dioxide, and water.

plant tissues

Groups of cells that work together to perform specific functions in plants.

leaf cross section

A cut through a leaf that shows the internal structure and organization of cells.

visualization

The process of forming a mental image to understand complex structures.

phloem

A type of tissue in plants that transports nutrients and sugars produced by photosynthesis.

xylem

A type of tissue in plants that transports water and minerals from the roots to the rest of the plant.

vascular bundle

A grouping of xylem and phloem that runs the length of the stem.

root hairs

Extensions of root cells that increase the surface area for water and mineral absorption.

cortex

The layer of cells in roots that usually do not contain chlorophyll and can store starch.

endodermis

The layer of cells in roots that helps control the transport of minerals between the cortex and vascular tissues.

pericycle

The layer of tissue that surrounds the phloem and xylem in roots and gives rise to branch roots.